Many electronic devices and systems include integrated circuits for the storage of data during the operation of the devices. For example, electronic devices such as computers, printing devices, scanning devices, personal digital assistants, calculators, computer work stations, audio and/or video devices, communications devices such as cellular telephones, and routers for packet switched networks may include memory in the form of integrated circuits for retaining data as part of their operation. Advantages of using integrated circuit memory compared to other forms of memory include space conservation and miniaturization, conserving limited battery resources, decreasing access time to data stored in the memory, and cutting the costs of assembling the electronic devices.
Dynamic Random Access Memory (DRAM) is an example of integrated circuit memory. DRAM typically comprises an array of semiconductor capacitor cells, each of which may hold an amount of electric charge that represents the logical value of a stored bit. The cells in the array are typically arranged in rows and columns. Each cell is situated at the intersection of a row and a column. Each cell in the DRAM array may be accessed by simultaneously addressing the intersecting row and column.
In operation, internal amplifiers in the DRAM sense the amounts of electric charges stored on the capacitors. Based on the sensed electric charges, the outputs of the sense amplifiers represent the logical values of the bits that are stored in the DRAM array. In this manner, the data stored in the array may be extracted from the DRAM integrated circuit for use by other integrated circuits in the electronic device. In addition, other internal circuitry on the DRAM refreshes the charge on those cells that the sense amplifiers have determined to already hold an electric charge. In this manner, the DRAM compensates for leakages of electric charge from the semiconductor capacitor cells, such as leakage into the substrate of the DRAM integrated circuit. Such reading, writing, and maintaining of charge on the cells are substantial internal operations of the DRAM.
The capacitors in DRAM cells can be containers and/or studs that are coupled to a cell contact. The containers and/or studs can move laterally, especially at the end of the container and/or stud that is not coupled to the cell contact. Containers and/or studs that move laterally and contact adjacent containers and/or studs can damage an array of DRAM cells and cause those DRAM cells to be inoperable.